1. Field of the Disclosure
The disclosure relates generally to the field of wireless communications. More particularly, the disclosure relates to allocation of resources for channel estimation.
2. Description of Related Art
In a wireless communication system, such as one implementing Orthogonal Frequency Division Multiple Access (OFDMA), the receiver can be configured to perform channel estimation as part of the demodulation process. The receiver may perform channel estimation in an OFDMA system to compensate for time varying frequency selective fading.
A receiver in an OFDMA system may perform channel estimation in a blind manner, without any knowledge of transmitted data, or may perform channel estimation based in part on one or more pilot channels that are broadcast and known to the receiver. In the configuration using pilot channels to aid receiver channel estimation, there is a trade off between the resources allocated to channel estimation and the system performance.
A communication system allocates a minimal number of pilot signals for channel estimation in order to maximize the available signal bandwidth. However, an inadequate allocation of resources to channel estimation may result in an inadequate channel estimate, which may result in the inability to demodulate received data and degradation of system performance.
Conversely, an allocation of excessive resources to channel estimation can ensure each receiver is able to determine an adequate channel estimate, but may burden the system and reduce its capacity. In this configuration, the system ensures the most degraded receiver is able to determine an accurate channel estimate at the cost of capacity of other better situated receivers.
It is desirable to allocate resources in a wireless communication system to allow for accurate channel estimation in receivers, but to minimize the allocation of resources such that channel capacity is not unnecessarily degraded.